Colorado Motor Vehicle Repair Act for Mobile Mechanics: Written Consent, the 10%/$25 Rule, and 3-Year Records

Updated 2026-10-17. Sources are listed at the end.

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This is general information, not legal or tax advice. Rules vary by state and change often. Confirm with the official source linked in each section, or with a licensed attorney, CPA or insurance agent, before you act.

Colorado has no state mechanic license. What it has is a strict estimate law, the Motor Vehicle Repair Act (C.R.S. 42-9-101 to 42-9-113), which applies to repair facilities. The overage limit is the main thing to know: 10% or $25, whichever is less. On most jobs that means $25.

Written consent. “No repairs on a motor vehicle shall be performed by a motor vehicle repair facility unless the facility obtains the written consent of the customer” (C.R.S. 42-9-104(1)(a)).
Written estimate of the total cost, including the expected completion date, with a copy to the customer (42-9-104(2)(a)).
Oral consent is allowed only when written consent wasn’t given. You must tell the customer the estimated total and record on the work order the date, time, manner of consent, phone number called, and the names of the people giving and receiving consent (42-9-104(1)(c)).
Cars that are towed in or left after hours can get up to $100 of labor and parts without the written consent. That’s mostly a shop situation, not a mobile one.

The waiver has exact wording

A customer can waive the estimate only by signing and dating, below this statement in bold type (42-9-104(2)(b)):

“I DO NOT WISH TO RECEIVE ANY ESTIMATE, EITHER WRITTEN OR ORAL, TO WHICH I AM ENTITLED BY LAW, BEFORE REPAIRS ARE AUTHORIZED.”

Signing the waiver is not authorization to do the repairs. That has to be a separate statement.

Going over the estimate: 10% or $25, whichever is less

Without the customer’s consent before the extra work, you can’t charge more than the estimate plus 10% or $25, whichever is less. Consent can be written or oral, but you must record it on the work order with the same details as above (C.R.S. 42-9-105(1)).

Estimate	10%	Limit without new consent
$150	$15	$165
$250	$25	$275
$600	$60	$625 (the $25 cap applies)

For a mobile tech, the practical result: any surprise part means a phone call or text first. Save the text thread and copy the details onto the work order.

Completion date changes

If the job will miss the expected completion date, tell the customer in writing on the work order, or orally with a record, within 24 hours after the original date (excluding weekends and holidays). A second change needs the customer’s consent. If either rule is broken, either side may cancel, and you may have to put the vehicle back together at no cost to the customer (unless you’ve already told them reassembly isn’t practical) (42-9-105(2)). If a part is back-ordered, call the customer that day.

Teardown, parts, and records

Disassembly to diagnose: the estimate must show the cost to reassemble if the customer declines, plus the cost of any parts normally destroyed by disassembly (42-9-104(2)(c)).
Returned parts: the work order must state conspicuously that the customer can have replaced parts back if they ask when authorizing. Warranty and exchange parts are shown, not returned, and airbag components are excluded (42-9-104(2)(a)(III)).
Keep the work order at least three years (42-9-104(2)(a)(IV)). That’s longer than many states require. Federal tax records have their own rules: how long to keep repair records.

Colorado-ready paperwork checklist

A work order with a consent signature line, an estimate total, an expected completion date, and the parts-return statement.
A separate bold waiver box with the exact statutory wording.
A consent log on each work order: date, time, manner, phone number, who gave consent, who received it.
Price your estimates accurately so you rarely need the $25 call. Use the job quote & profit calculator.
Keep work orders for 3 years.

Compare other states in what must be on an auto repair estimate and invoice and Washington’s Automotive Repair Act.

Sources

C.R.S. 42-9-104, When consent and estimate required (original transaction; disassembly): https://colorado.public.law/statutes/crs_42-9-104
C.R.S. 42-9-105, When consent and estimate required (additional repairs; changed completion date): https://colorado.public.law/statutes/crs_42-9-105
Colorado Revised Statutes Title 42 (official PDF, Office of Legislative Legal Services): https://leg.colorado.gov/sites/default/files/images/olls/crs2024-title-42.pdf